drivers/clk/uniphier/clk-uniphier-cpugear.c

   1 /*
   2  * Copyright (C) 2016 Socionext Inc.
   3  *   Author: Masahiro Yamada <yamada.masahiro@socionext.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/clk-provider.h>
  17 #include <linux/device.h>
  18 #include <linux/regmap.h>
  19
  20 #include "clk-uniphier.h"
  21
  22 #define UNIPHIER_CLK_CPUGEAR_STAT       0       /* status */
  23 #define UNIPHIER_CLK_CPUGEAR_SET        4       /* set */
  24 #define UNIPHIER_CLK_CPUGEAR_UPD        8       /* update */
  25 #define   UNIPHIER_CLK_CPUGEAR_UPD_BIT  BIT(0)
  26
  27 struct uniphier_clk_cpugear {
  28         struct clk_hw hw;
  29         struct regmap *regmap;
  30         unsigned int regbase;
  31         unsigned int mask;
  32 };
  33
  34 #define to_uniphier_clk_cpugear(_hw) \
  35                         container_of(_hw, struct uniphier_clk_cpugear, hw)
  36
  37 static int uniphier_clk_cpugear_set_parent(struct clk_hw *hw, u8 index)
  38 {
  39         struct uniphier_clk_cpugear *gear = to_uniphier_clk_cpugear(hw);
  40         int ret;
  41         unsigned int val;
  42
  43         ret = regmap_write_bits(gear->regmap,
  44                                 gear->regbase + UNIPHIER_CLK_CPUGEAR_SET,
  45                                 gear->mask, index);
  46         if (ret)
  47                 return ret;
  48
  49         ret = regmap_write_bits(gear->regmap,
  50                                 gear->regbase + UNIPHIER_CLK_CPUGEAR_UPD,
  51                                 UNIPHIER_CLK_CPUGEAR_UPD_BIT,
  52                                 UNIPHIER_CLK_CPUGEAR_UPD_BIT);
  53         if (ret)
  54                 return ret;
  55
  56         return regmap_read_poll_timeout(gear->regmap,
  57                                 gear->regbase + UNIPHIER_CLK_CPUGEAR_UPD,
  58                                 val, !(val & UNIPHIER_CLK_CPUGEAR_UPD_BIT),
  59                                 0, 1);
  60 }
  61
  62 static u8 uniphier_clk_cpugear_get_parent(struct clk_hw *hw)
  63 {
  64         struct uniphier_clk_cpugear *gear = to_uniphier_clk_cpugear(hw);
  65         int num_parents = clk_hw_get_num_parents(hw);
  66         int ret;
  67         unsigned int val;
  68
  69         ret = regmap_read(gear->regmap,
  70                           gear->regbase + UNIPHIER_CLK_CPUGEAR_STAT, &val);
  71         if (ret)
  72                 return ret;
  73
  74         val &= gear->mask;
  75
  76         return val < num_parents ? val : -EINVAL;
  77 }
  78
  79 static const struct clk_ops uniphier_clk_cpugear_ops = {
  80         .determine_rate = __clk_mux_determine_rate,
  81         .set_parent = uniphier_clk_cpugear_set_parent,
  82         .get_parent = uniphier_clk_cpugear_get_parent,
  83 };
  84
  85 struct clk_hw *uniphier_clk_register_cpugear(struct device *dev,
  86                                          struct regmap *regmap,
  87                                          const char *name,
  88                                 const struct uniphier_clk_cpugear_data *data)
  89 {
  90         struct uniphier_clk_cpugear *gear;
  91         struct clk_init_data init;
  92         int ret;
  93
  94         gear = devm_kzalloc(dev, sizeof(*gear), GFP_KERNEL);
  95         if (!gear)
  96                 return ERR_PTR(-ENOMEM);
  97
  98         init.name = name;
  99         init.ops = &uniphier_clk_cpugear_ops;
 100         init.flags = CLK_SET_RATE_PARENT;
 101         init.parent_names = data->parent_names;
 102         init.num_parents = data->num_parents,
 103
 104         gear->regmap = regmap;
 105         gear->regbase = data->regbase;
 106         gear->mask = data->mask;
 107         gear->hw.init = &init;
 108
 109         ret = devm_clk_hw_register(dev, &gear->hw);
 110         if (ret)
 111                 return ERR_PTR(ret);
 112
 113         return &gear->hw;
 114 }